Compound, adhesive article, and methods of making the same

ABSTRACT

A method of making an adhesive article comprises three steps. First, a backing is provided having first and second opposed major surfaces with respective first and second silicone release layers disposed thereon. The second silicone release layer further comprises a compound represented by the formula: R 1  represents a divalent hydrocarbon radical having from 2 to 40 carbon atoms or covalent bond. R 2  represents a monovalent or divalent poly(dimethylsiloxane) moiety. X represents —NH— or a covalent bond. R f  represents a perfluorinated group having from 3 to 5 carbon atoms. y is 1 or 2. Second, an adhesive layer is disposed onto the first silicone release layer. Third, the adhesive layer is exposed to E-beam radiation within a process chamber containing oxygen to provide a crosslinked adhesive layer. An adhesive article made by the method and the compound are also disclosed.

TECHNICAL FIELD

The present disclosure broadly relates to fluorinated compositions,adhesive articles, and methods of making them.

BACKGROUND

Adhesive tape comes in many varieties; for example, single-sided ordouble-sided tape, typically wound into a roll. Double-sided adhesivetape (also termed “adhesive transfer tapes”) has adhesive properties onboth sides, generally covered by a liner to protect the adhesive, whichis removed prior to when the adhesive layer is bonded to a substrate. Insome embodiments, a double-sided release liner is used, wherein a firstrelease layer is coated on a first major surface of a backing, and asecond release layer is coated on a second major surface of the backingopposite the first major surface. Typically, the first and secondrelease layers are designed to have different release properties tofacilitate dispensing the tape in roll form. For example, the firstrelease layer may bind somewhat more tightly to the adhesive layer thanthe second release layer in order to achieve a clean unwind of the roll.

Methods of producing double-sided adhesive tape can be relativelysimple, and one method of production and the resulting structure is asfollows. A layer of an adhesive composition is readied and extruded, orotherwise coated by some acceptable method, onto the first release layerof the release liner. For high performance adhesive tapes, the adhesivecomposition is often then crosslinked (e.g., chemically, by visible orultraviolet light, or by electron beam radiation). Next, thedouble-sided release liner and adhesive construction is wound into aroll such that the adhesive layer is sandwiched between the first andsecond release layers.

Production of double-sided adhesive tape by this method is desirable,but significant problems are encountered when electron beam (“E-Beam”)radiation is used to crosslink the adhesive polymer. E-Beam radiation isadvantageous as a method of crosslinking because it is effective tocrosslink adhesive polymers that have high amounts of pigments orfillers, and/or adhesive films of greater thicknesses. In tapeconstructions with a single double-sided liner, it is typicallynecessary to perform the electron beam (E-Beam) exposure step with amajor surface of the silicone release layer exposed (the exposedsurface) to the ambient environment of the E-Beam processing chamber. Ifthe exposed surface of the silicone release layer is exposed to E-Beamradiation (“E-Beam treated”) before winding into a roll, the releaseproperties of the silicone release layer as adhered to the adhesivelayer itself are typically altered in a deleterious fashion.

Moreover, in this configuration the adhesive bond between the adhesivelayer and the release layer onto which it is subsequently wound tends toincrease over time, leading to unpredictable product performance. Thiscan create an undesirable situation in the final product wherein theadhesion of the adhesive layer to both release layers is comparable,resulting in what is known as “liner confusion”. In some cases, therelease liner cannot even be removed. This is known as “liner blocking”.Even when the adhesive material is E-Beam treated directly (i.e., notthrough a release liner), the side of the silicone release layeropposite the adhesive material will typically be affected if theradiation penetrates through the liner.

One solution to this problem has been to manufacture the double-sidedadhesive tape on a temporary liner, crosslink the adhesive with E-Beamradiation, and then replace the temporary release liner with anotherrelease liner before it is packaged into the final product. However,this solution is unacceptable because it adds to the complexity of theprocess, increases waste of the process, and adds the additional cost ofanother liner. Therefore, there is a need for a release liner that canbe E-Beam treated while still maintaining essentially the samepre-E-Beam treated release characteristics so that it need not bereplaced before the consumer can utilize the final product.

SUMMARY

Without wishing to be bound by theory, Applicants believe that thedetrimental effect of E-beam exposure on the open side of the adhesivelayer (discussed above) and exposed silicone release layer leads toformation of various chemical species (e.g., peroxide groups and/orperoxy radicals) that chemically transform the adhesive and releasematerial surfaces as well as their interface over time, therebycontributing to the problems enumerated above.

Advantageously, the present disclosure describes methods of overcomingthe aforementioned problems, without the need for a costly temporaryrelease liner.

Accordingly, in one aspect the present disclosure provides a method ofmaking an adhesive article, the method comprising:

providing a backing having first and second opposed major surfaces,wherein a first silicone release layer is disposed on the first majorsurface, wherein a second silicone release layer is disposed on thesecond major surface, and wherein the second silicone release layerfurther comprises a compound represented by the formula:

-   -   wherein        -   R¹ represents a divalent hydrocarbon radical having from 2            to 40 carbon atoms or covalent bond;        -   R² represents a monovalent or divalent            poly(dimethylsiloxane) moiety;        -   X represents —NH— or a covalent bond;        -   R_(f) represents a perfluorinated group having from 3 to 5            carbon atoms; and        -   y is 1 or 2;

disposing an adhesive layer onto the first silicone release layer; and

exposing at least the adhesive layer to electron beam radiation within aprocess chamber thereby providing a crosslinked adhesive layer, whereinthe process chamber contains oxygen, wherein the second silicone releaselayer is exposed to the oxygen during crosslinking of the adhesivelayer.

In another aspect, the present disclosure provides an adhesive articlemade according to the preceding method of the present disclosure.

In yet another aspect, the present disclosure provides an adhesivearticle comprising: a backing having first and second opposed majorsurfaces, wherein a first silicone release layer is disposed on thefirst major surface, wherein a second silicone release layer is disposedon the second major surface, and wherein the second silicone releaselayer further comprises a compound represented by the formula:

-   -   wherein        -   R¹ represents a divalent hydrocarbon radical having from 2            to 40 carbon atoms or covalent bond;        -   R² represents a monovalent or divalent            poly(dimethylsiloxane) moiety;        -   X represents —NH— or a covalent bond;        -   R_(f) represents a perfluorinated group having from 3 to 5            carbon atoms; and        -   y is 1 or 2; and

an adhesive layer sandwiched between the first and second releaselayers.

In yet another aspect, the present disclosure provides a compoundrepresented by the formula:

-   -   wherein        -   R¹ represents a divalent hydrocarbon radical having from 2            to 40 carbon atoms or covalent bond;        -   R² represents a monovalent or divalent            poly(dimethylsiloxane) moiety;        -   X represents —NH— or a covalent bond;        -   R_(f) represents a perfluorinated group having from 3 to 5            carbon atoms; and        -   y is 1 or 2.

As used herein:

The chemical group “Me” refers to methyl.

The term “moiety” refers to a contiguous portion of a molecule which maybe a monovalent group or a polyvalent group (e.g., a divalent group).

The term “pressure-sensitive adhesive” (PSA) refers to an adhesivecharacterized by being normally tacky at room temperature (e.g., 20degrees Celsius (° C.)) and forming a bond to a surface by theapplication of, at most, very light finger pressure. PSAs possess abalance of viscoelastic and elastic properties which result in afour-fold balance of adhesion, cohesion, stretchiness and elasticity.They have sufficient cohesiveness and elasticity so that they can behandled and removed from surfaces without leaving a residue even thoughthey are tacky. PSAs do not embrace compositions merely because they aresticky or adhere to a substrate.

The term “perfluorinated” in reference to a chemical species (e.g.,group or molecule) means that all hydrogen atoms in the species havebeen replaced by fluorine.

The term “siliconized release liner” refers to a liner (e.g., a tape orsheet) having silicone release layers on opposed major surfaces thereof.

Features and advantages of the present disclosure will be furtherunderstood upon consideration of the detailed description as well as theappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a vertical cross-section of anexemplary double-sided adhesive tape according to the presentdisclosure.

FIG. 2 is a schematic representation of an exemplary method of windingup double-sided adhesive tape in to a roll.

FIG. 3 is a schematic representation of an exemplary process for makinga double-sided adhesive tape according to the present disclosure.

Repeated use of reference characters in the specification and drawingsis intended to represent the same or analogous features or elements ofthe disclosure. It should be understood that numerous othermodifications and embodiments can be devised by those skilled in theart, which fall within the scope and spirit of the principles of thedisclosure. The figures may not be drawn to scale.

DETAILED DESCRIPTION

FIG. 1 depicts a vertical cross-section of one configuration of adouble-sided adhesive tape 10 after its production and before it hasbeen packaged. The double-sided adhesive tape 10 includes an adhesivelayer 12. Polymers that can be used in the adhesive layer 12 arediscussed more fully below. The adhesive layer 12 is generally formed ina sheet and has a first surface 11 and a second surface 13. When thedouble-sided adhesive tape 10 is produced, the method of productionleaves the first surface 11 of the adhesive layer 12 uncovered.

The double-sided adhesive tape 10 also includes a siliconized releaseliner 20. The siliconized release liner 20 includes a backing 21.Suitable materials for the backing 21 are discussed more fully below.The backing 21 has a first surface 23 and a second surface 24. Thesiliconized release liner 20 includes a first silicone release layer 22and a second silicone release layer 25. While FIG. 1 shows siliconizedrelease liner 20 with first silicone release layer 22, backing 21 mayhave sufficient liner release such that first silicone release layer 22is not necessary. If used, first silicone release layer 22 is applied tothe first surface 23 of the backing 21. The second silicone releaselayer 25 is applied to the second surface 24 of the backing 21. Thefirst silicone release layer 22 has a release side 27 next to the secondsurface 13 of the adhesive layer 12 and a backing side 28. The releaseside 27 of the first silicone release layer 22 also defines a firstsurface 23 of siliconized release liner 20. The second silicone releaselayer 25 has a backing side 29 and a non-backing side 30. Thenon-backing side 30 of the second silicone release layer 25 also definesa second surface 32 of siliconized release liner 20. The first andsecond silicone release layers 22 and 25 can be composed of the same ordifferent material. Preferably, the first and second silicone releaselayers (22, 25) are composed of different materials.

FIG. 2 depicts one method of readying a double-sided adhesive tape 10for packaging. The double-sided adhesive tape 10 is wound around itselfinto a roll to form a packageable article 50. In use, double-sidedadhesive tape is unwound, optionally cut, and applied to a surface withthe exposed side of the adhesive layer 12 (the first side 11 discussedabove) and the backing 21 is then removed. Optionally, the second side13 of the adhesive layer 12 is applied to a second surface after thebacking 21 is removed. This method of forming a packageable article 50results in portions of the double-sided adhesive tape 10 interactingwith other portions of the double-sided adhesive tape 10. Once thedouble-sided adhesive tape 10 begins to be wound on itself, the firstsurface 11 of the adhesive layer 12 comes into contact with thenon-backing side 30 of the second silicone release layer 25 (alsoreferred to as the second surface 32 of siliconized release liner 20).

The contact of the non-backing side 30 of the second silicone releaselayer 25 and the first surface 11 of the adhesive layer 12 becomesimportant when the packageable article 50 is unrolled to use thedouble-sided adhesive tape 10. It is desirable that the adhesive layer12 and the siliconized release liner 20 maintain contact through thesecond surface 13 instead of the first surface 11 of the adhesive layer12. Therefore, the siliconized release liner 20 should releasepreferentially from the first surface 11 before it releases from thesecond surface 13 of the adhesive layer 12. Thus, the siliconizedrelease liner 20 should have a liner release from the first surface 11of the adhesive layer 12 that is sufficiently different from the linerrelease from the second surface 13 of the adhesive layer 12. The secondsurface 32 of siliconized release liner 20 and adhesive layer 12 areconfigured so that this differential effect is developed. Preferably,the ratio of release forces from the first release layer and the secondrelease layer is at least 2:1, more preferably at least 3:1.

FIG. 3 schematically depicts one method of producing double-sidedadhesive tape 10 and forming it into a packageable article 50. Theadhesive layer 12 is dispensed from a dispenser 101 onto a siliconizedrelease liner 20. Next the siliconized release liner 20 and the adhesivelayer 12 are laminated together between a pair of nip rollers 102 toform the double-sided adhesive tape 10. Then, the double-sided adhesivetape 10 is exposed to radiation from a radiation source 103 through thesiliconized release liner 20 to cause crosslinking of the adhesive layer12. The radiation source 103 is preferably an E-Beam source. Thedouble-sided adhesive tape 10 is then formed into a packageable article50 by winding upon itself to form a roll.

The siliconized release liner has a backing with first and secondopposed major surfaces (23, 24). First and second silicone releaselayers (22, 25) are disposed on the respective surfaces of the backing21.

Suitable materials for the backing 21 include, for example, polymericfilms, such as polyester films (e.g., polyethylene terephthalate films)and polyolefin films (e.g., polyethylene films, polypropylene films,biaxially-oriented polypropylene films (BOPP films)), metallized film,sealed paper (e.g., polyethylene-coated paper, metallized paper, andclay-coated paper), and paper.

The first silicone release layer 22 on the first surface 23 of thebacking 21 can include conventional silicone release materials,including those that are known in the art such as, e.g., chemistriesusing the following curing mechanisms: condensation cure (e.g.,hydrolytic), addition cure (e.g., hydrosilation-based), free-radicalcure, cationic cure, and triggered condensation cure. Details concerningthese silicone chemistries can be found in, for example, U.S. Pat. No.4,504,645 (Melancon), U.S. Pat. No. 4,600,484 (Drahnak), and U.S. Pat.No. 7,279,210 (Hulteen et al.), PCT Publication No. WO 98/40439 (Liu etal.) and Handbook of Pressure Sensitive Adhesive Technology, 3rd ed.,Chapters 23 and 24, Van Nostrand Reinhold Co., Inc. (1989).

The second silicone release layer 25 on the second surface 24 of thebacking 21 can also include conventional silicone release materials.Preferably, the second silicone release layer materials comprise tightlycrosslinked siloxane networks with minimal polar or reactivefunctionalities, especially free-radical reactive functionalities. It isknown that chemical bond cleavage will occur from excited states in anirradiated polymer when a polymer is exposed to E-Beam radiation, whichleads to free radical formation. The free radicals formed have a shortlife and will either recombine with other free-radicals to lose theirreactivity, react with a polymer, or react with other functional groupsto create free radicals having a longer life. The relatively long-livedfree radicals can further react with molecular oxygen, for example, andgive a relatively stable peroxide compound when the irradiated materialis exposed to an oxygen containing environment (i.e.,radiation-oxidation).

Thus formed peroxides have a relatively longer life, so that they may beable to migrate to the adhesive-release interface to further react (orinteract) with the adhesive. This causes higher liner release values(meaning that a relatively undesirable high unwind force is required) orliner blocking. To minimize liner blocking and make the second siliconerelease layer 25 function in the desired way, the silicone release layermaterial should contain minimal free-radical-reactive functionalities,such as the acrylate, methacrylate, vinyl, and silicon hydridefunctionalities.

The present inventors have found, unexpectedly, that a release linercoated with a silicone release composition containing certainfluorinated additives, provides acceptable release after exposing therelease layer to electron beam radiation.

Silicone or polydimethylsiloxane is the most important and widely usedrelease material. To reduce or avoid silicone transfer to the adhesivelayer the silicone release layer is generally crosslinked. Crosslinkingcan be either physical crosslinking or chemical crosslinking. Chemicalcrosslinking is also referred to as “curing” in this patent application.

Among the silicone cure chemistries, free-radical cure, addition cure,and condensation cure all may give crosslinked networks.

Crosslinked silicones are typically derived from at least onecorresponding reactive silicone precursor that includes two or morereactive groups. The reactive groups preferably include epoxy, acrylate,silane, silanol, or ethylenically-unsaturated (e.g., vinyl or hexenyl)groups. Silicone precursors that include two or more epoxy or acrylategroups will typically homopolymerize without the need for a separatecrosslinker. The silicone precursors that include two or more, silanol,or ethylenically-unsaturated groups use a separate crosslinker, such asa hydride-functional silicone crosslinker. Alternatively, a silanol,alkoxysilane, or acyloxysilane-functional silicone precursor can bereacted with an alkoxy-functional crosslinker, as described in U.S. Pat.No. 6,204,350 (Liu et al.).

In some embodiments, the number average molecular weight betweenfunctional groups of the silicone base precursor is less than about500000 g/mol, preferably less than about 20000 or less. In someembodiments, the number average molecular weight between functionalgroups is at least about 500 g/mol, and often at least about 2,000g/mol.

Suitable epoxy-functional silicone precursors are described, forexample, in U.S. Pat. No. 4,279,717 (Eckberg et al.) and U.S. Pat. No.5,332,797 (Kessel et al.). Examples of epoxy-functional siliconeprecursors include, for example, those available as SILFORCE UV 9400,SILFORCE UV 9315, SILFORCE UV 9430, SILFORCE UV 9600, all available fromMomentive, Columbus, Ohio, and as SILCOLEASE UV200 series from BluestarSilicones, East Brunswick, N.J.

Suitable acrylate-functional silicone precursors are described, forexample, in U.S. Pat. No. 4,348,454 (Eckberg). Examples ofacrylate-functional silicone precursors include, for example, thoseavailable as SILCOLEASE UV100 Series, from Bluestar Silicones, and thoseavailable as TEGO RC 902, TEGO RC 922, and TEGO RC 711, from EvonikIndustries, Parsippany, N.J.

Suitable silanol-functional silicone polymers are well known and areavailable from a variety of sources including, e.g., those available asDMS-S12 and DMS-S21 from Gelest, Inc., Morrisville, Pa.

Suitable ethylenically-unsaturated functional silicone precursorsinclude polydimethylsiloxanes with pendant and/or terminal vinyl groups,as well as polydimethylsiloxanes with pendant and/or terminal hexenylgroups. Suitable hexenyl functional silicones are described, forexample, in U.S. Pat. No. 4,609,574 (Keryk et al.). An example of ahexenyl-functional silicone includes, for example, one available asSYL-OFF 7677, available from Dow Corning, Midland, Mich. Suitablevinyl-functional silicones are described, for example, in U.S. Pat. No.3,814,731 (Nitzsche et al.) and U.S. Pat. No. 4,162,356 (Grenoble), andare available from a wide variety of sources. Examples ofvinyl-terminated polydimethylsiloxane include those available as DMS-V21(molecular weight=6000) and DMS-V25 (molecular weight=17,200), fromGelest Inc. Suitable vinyl-functional silicone polymers are alsoavailable as SYL-OFF from Dow Corning. An exemplary material containingend-blocked and pendant vinyl-functional silicone polymers is SYL-OFF7680-020 polymer from Dow Corning.

Suitable hydride-functional silicone crosslinkers are described, forexample, in U.S. Pat. No. 3,814,731 (Nitzsche et al.) and U.S. Pat. No.4,162,356 (Grenoble). Suitable crosslinkers are well known, and one ofordinary skill in the art would be readily able to select an appropriatecrosslinker, including identifying appropriate functional groups on suchcrosslinkers, for use with a wide variety of silicone-based polymers.For example, hydride-functional crosslinkers are available as SYL-OFFfrom Dow Corning, including those available as SYL-OFF 7048 and SYL-OFF7678. Other exemplary hydride-functional crosslinkers include thoseavailable as SS4300C and SL4320, available from Momentive PerformanceMaterials, Albany, N.Y.

The hydride equivalent weight of a hydride-functional siliconecrosslinker is typically at least about 60 grams per equivalent (g/eq),and typically no greater than about 150 g/eq.

In embodiments including a silanol-functional silicone precursor and ahydride functional crosslinker, the equivalent ratio of hydride groupsto silanol groups is preferably at least about 1.0 (1:1) and often nomore than about 25.0 (25:1).

In embodiments including an ethylenically-unsaturated functionalsilicone precursor and a hydride functional crosslinker, the equivalentratio of hydride groups to ethylenically-unsaturated groups ispreferably at least about 1.0 (1:1), and more preferably at least about1.1. Often, the equivalent ratio is no more than about 2.0 (2:1) andmore often no more than about 1.5.

Suitable alkoxy-functional crosslinkers, and conditions of crosslinking,including relative amounts of crosslinker, are described in U.S. Pat.No. 6,204,350 (Liu et al.).

The crosslinked (e.g., cured) silicone described herein may be derivedfrom one or more reactive silicone precursors crosslinked using acatalyst. Examples of suitable catalysts are described, for example, inU.S. Pat. No. 5,520,978 (Boardman et al.). Preferably, the catalyst is aplatinum or rhodium catalyst for vinyl- and hexenyl-functionalsilicones. Preferably, the catalyst is a tin catalyst for silanolfunctional silicones. Examples of commercially available platinumcatalysts include, but are not limited to, those available under thetrade designation SIP6831.2 (a platinum-divinyltetramethyldisiloxanecatalyst complex in xylene; 2.1-2.4 weight percent platinumconcentration), available from Gelest Inc. The amount of Pt is typicallyabout 60 to about 150 parts per million (ppm) by weight.

Other components used in making silicone release layers include, forexample, inhibitors such as, e.g., a diallyl maleate inhibitor availableas SL 6040-D1 01P, from Momentive, MQ resins such as that available asSYL-OFF 7210 RELEASE MODIFIER from Dow Corning, and anchorage additivessuch as that available as SYL-OFF 297 available from Dow Corning.

Improved release stability for siliconized release liners that areexposed to E-Beam radiation in the presence of oxygen is achieved byincluding at least one compound represented by Formula (I), below:

in the silicone release layer formulation, e.g., the first siliconerelease layer in adhesive articles according to the present disclosure.

R¹ represents a divalent hydrocarbon radical having from 2 to 40 carbonatoms or a covalent bond. R¹ can be aliphatic or aromatic, cyclic,linear, or branched. In some embodiments, R¹ has 6 carbon atoms and isaromatic (e.g., p-phenylene, m-phenylene, or o-phenylene). In someembodiments, R¹ has 2 to 20 carbon atoms, 2 to 12 carbon atoms, 2 to 6carbon atoms, or 2 to 4 carbon atoms. Examples include ethylene (i.e.,—CH₂CH₂—), propane-1,3,-diyl, propane-1,2-diyl, butane-1,4,-diyl,hexane-1,6-diyl, cyclohexane-1,6-diyl, dodecane-1,12-diyl,dodecane-1,6-diyl, hexadecane-1,16-diyl, eicosane-1,20-diyl.

R² represents a monovalent (y=1) or divalent poly(dimethylsiloxane)(y=2) moiety. In some embodiments, the polydimethylsiloxane moiety has anumber average (M_(n)) molecular weight of from at least 250 g/mole(g/mol), at least 500 g/mol, at least 1000 g/mol, at least 2000 g/mol,or at least 2500 g/mol up to at least 5000 g/mole, at least 7500 g/mol,or more. Alternatively, or in addition, in some embodiments, thepolydimethylsiloxane moiety contains an average of from at least 2, atleast 3, at least 4, at least 5, at least 10, at least 20, at least 30,or even at least 40 silicon atoms up to 50 silicon atoms, or more.

X represents —NH— or a covalent bond.

R_(f) represents a perfluorinated group having from 3 to 5 carbon atoms.Examples include perfluoro-n-propyl, perfluoro-iso-propyl,perfluoro-n-butyl, perfluoro-iso-butyl, perfluoro-t-butyl,perfluoro-n-pentyl, perfluoro-sec-pentyl, and perfluoro-neo-pentyl.

y is 1 or 2.

Compounds according to Formula (I) can be made according to conventionalsynthetic approaches. For example, the fluorinated acrylamide shown inFormula II (below), wherein R_(f) is as described in Formula I(hereinbefore), can be prepared according to the procedures in U.S.Provisional Pat. Appl. No. 62/266,035, filed Dec. 11, 2015, and entitled“FLUOROCHEMICAL PIPERAZINE SULFONAMIDES”.

This fluorinated olefin can be coupled by hydrosilation with ahydrogen-terminated polydimethylsiloxane as shown below:

or a α,ω-dihydridopoly(dimethylsiloxane) as shown below:

wherein j is an integer greater than or equal to 1, preferably greaterthan or equal to 2, more preferably greater than or equal to 4. Suchcoupling reactions result in compounds according to Formula I whereiny=1 and y=2, respectively. The coupling reaction may be carried out intoluene solvent using Karstedt's catalyst (i.e.,platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane, typically sold asa solution in toluene), for example. Other hydrosilation catalysts mayalso be used.

Mono- and di-hydride-terminated polydimethylsiloxanes can be preparedaccording to known methods and/or obtained from commercial suppliers;for example, from Aldrich Chemical Co., Milwaukee, Wis. or Dow Corning,Midland, Mich.

Compounds according to Formula II can be prepared using known organicreactions such as, for example, those disclosed in U.S. Pat. No.5,451,622 (Boardman et al.). An exemplary method of preparation is bythe reaction of fluoroaliphatic sulfonyl fluorides, R_(f)SO₂F, withpiperazine followed by reaction of the resulting fluoroaliphaticradical-containing sulfonylpiperazine with various organic reactants(e.g., acid halides having alkenyl groups, isocyanates having alkenylgroups). Analogous reactions for preparing other compounds will beapparent to those of ordinary skill in the art.

Any suitable methods can be used to coat the silicone release layers onthe backing. Typical silicone release layer weights are greater than 0.2g/m² and more typically are from 0.7 g/m² to 2.5 g/m². Liner releasevalues observed with siliconized release liners that have been E-Beamtreated vary both with coating weight and the specific backing utilized.

Compounds of Formula I are included in the second silicone release layerin a total amount that is effective to substantially eliminate linerconfusion. Preferably, the compound is included in the second siliconerelease layer in an amount of 0.1 to 10 weight percent, more preferably0.1 to 6 percent, and even more preferably 0.5 to 6, although otheramounts can also be used.

Additives such as for example, fillers, antioxidants, viscositymodifiers, pigments, release modifiers can be added to both the firstand second silicone release layers (22 and 25) to the extent that theydo not substantially and deleteriously alter the desired properties ofthe final product.

Once silicone release layer formulations are chosen, the components aremixed and delivered to a coater. Useful coating methods include, forexample, bar coating; roll coating (e.g., gravure coating, offsetgravure coating (also called 3-roll coating), and 5-roll coating); spraycoating; curtain coating; and brush coating.

The silicone release layer formulations are coated directly onto thebacking, either from 100% solids or from a solution. Useful backingsinclude, but are not limited to, polyester (e.g., PET), polyolefin(e.g., polyethylene, polypropylene, biaxially oriented polypropylene(BOPP)), polycoated paper, metallized paper, clay sealed paper, andmetallized films. The surfaces of the backing may be further treated toenhance silicone release layer anchorage to the backing chemically orphysically, for example, with a primer, corona treatment, or flametreatment.

After each curable silicone release layer formulation is coated onto thebacking, the coated curable silicone release layer formulation is cured,for example, by ultraviolet (UV) or thermal radiation, depending on therequirements of the system. Examples of useful UV lights include highintensity UV lights, such as H-type lamps (commercially available fromFusion UV Curing Systems, Rockville, Md.) and medium pressure mercurylamps. When solvent-based formulations are used as silicone releaselayers, treatment in a thermal oven also may be needed before UV curingto remove solvents.

This general procedure works for both the first silicone release layer21 and second silicone release layer 25. Generally, the first siliconerelease layer 21 is coated before the second silicone release layer 25.Alternatively, both of the first and second silicone release layers 21,25 may be coated and cured at the same time.

A variety of different polymer resins, as well as blends thereof, aresuitable for forming the adhesive layer 12. The particular resin isselected based upon the desired properties of the final article. Anexample of a class of polymer resins useful in the adhesive layer 12 canbe found in U.S. Pat. No. 6,103,152 (Gehlsen et al.). It may bedesirable to blend two or more acrylate polymers having differentchemical compositions. A wide range of physical properties can beobtained by manipulation of the type and concentration of the blendcomponents.

One class of polymers useful for the adhesive layer 12 includes acrylateand methacrylate polymers and copolymers. Such polymers are formed, forexample, by polymerizing one or more monomeric acrylic or methacrylicesters of non-tertiary alkyl alcohols, with the alkyl groups having from1 to 20 carbon atoms (e.g., from 3 to 18 carbon atoms). Suitableacrylate monomers include, for example, methyl acrylate, ethyl acrylate,n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, cyclohexylacrylate, iso-octyl acrylate, octadecyl acrylate, nonyl acrylate, decylacrylate, and dodecyl acrylate. The corresponding methacrylates areuseful as well. Also useful are aromatic acrylates and methacrylates(e.g., benzyl acrylate and benzyl methacrylate).

Optionally, one or more monoethylenically unsaturated co-monomers may bepolymerized with the acrylate or methacrylate monomers. The particulartype and amount of co-monomer is selected based upon the desiredproperties of the polymer. One group of useful co-monomers includesthose having a homopolymer glass transition temperature greater than theglass transition temperature of the (meth)acrylate (i.e., acrylate ormethacrylate) homopolymer. Examples of suitable co-monomers fallingwithin this group include: acrylic acid; acrylamides; methacrylamides;substituted acrylamides (such as N,N-dimethylacrylamide); itaconic acid;methacrylic acid; acrylonitrile; methacrylonitrile; vinyl acetate;N-vinylpyrrolidone; isobornyl acrylate; cyanoethyl acrylate;N-vinylcaprolactam; maleic anhydride; hydroxyalkyl (meth)acrylates;N,N-dimethylaminoethyl (meth)acrylate; N,N-diethylacrylamide;beta-carboxyethyl acrylate; vinyl esters of neodecanoic, neononanoic,neopentanoic, 2-ethylhexanoic, or propionic acids; vinylidene chloride;styrene; vinyltoluene, and alkyl vinyl ethers.

A second group of monoethylenically unsaturated co-monomers that may bepolymerized with the acrylate or methacrylate monomers includes thosehaving a homopolymer glass transition temperature (T_(g)) less than theglass transition temperature of the acrylate homopolymer. Examples ofsuitable co-monomers falling within this class includeethyloxyethoxyethyl acrylate (T_(g)=−71 degrees Celsius (° C.)) and amethoxypolyethylene glycol 400 acrylate (T_(g)=−65° C.; available fromShin Nakamura Chemical Co., Ltd. as NK Ester AM-90G).

A second class of polymers useful in the adhesive layer 12 includes:semicrystalline polymer resins, such as polyolefins and polyolefincopolymers (e.g., polymer resins based upon monomers having between 2and 8 carbon atoms, such as low-density polyethylene, high-densitypolyethylene, polypropylene, and ethylene-propylene copolymers);polyesters and co-polyesters; polyamides and co-polyamides; fluorinatedhomopolymers and copolymers; polyalkylene oxides (e.g., polyethyleneoxide and polypropylene oxide); polyvinyl alcohol; ionomers (e.g.,ethylene-methacrylic acid copolymers neutralized with a base); andcellulose acetate. Other examples of polymers in this class includeamorphous polymers such as polyacrylonitrile polyvinyl chloride,thermoplastic polyurethanes, aromatic epoxies, polycarbonates, amorphouspolyesters, amorphous polyamides, ABS block copolymers, polyphenyleneoxide alloys, ionomers (e.g., ethylene-methacrylic acid copolymersneutralized with salt), fluorinated elastomers, and polydimethylsiloxane.

A third class of polymers useful in the adhesive layer 12 includeselastomers containing ultraviolet radiation-activatable groups. Examplesinclude polybutadiene, polyisoprene, polychloroprene, random and blockcopolymers of styrene and dienes (e.g., SBR), andethylene-propylene-diene monomer rubber. This class of polymer istypically combined with tackifying resins.

A fourth class of polymers useful in the adhesive layer 12 includespressure-sensitive and hot melt applied adhesives prepared fromnon-photopolymerizable monomers. Such polymers can be adhesive polymers(i.e., polymers that are inherently adhesive), or polymers that are notinherently adhesive but are capable of forming adhesive compositionswhen compounded with components such as plasticizers, or tackifiers.Specific examples include poly-alpha-olefins (e.g., polyoctene,polyhexene, and atactic polypropylene), block copolymer-based adhesives,natural and synthetic rubbers, silicone adhesives, ethylene-vinylacetate, and epoxy-containing structural adhesive blends (e.g.,epoxy-acrylate and epoxy-polyester blends).

The adhesive layer 12 may also optionally have other components in it.Normal additives such as, for example, fillers, antioxidants, viscositymodifiers, pigments, tackifying resins, fibers, and the like can also beadded to the adhesive layer 12, to the extent that they do not alter thedesired properties of the final product.

A preferred optional additive is a pigment, or a light blocking fillers.Any compound generally used as a pigment can be utilized, as long as thedesired properties of the final product are not altered thereby.Exemplary pigments include carbon black and titanium dioxide. The amountof pigment also depends on the desired use of the product. Generally,the concentration of pigment is greater than 0.10% by weight.Preferably, the concentration of pigment is greater than 0.15% byweight, and more preferably greater than 0.18% by weight to give theadhesive layer 12 an opaque color.

The thickness of the adhesive layer 12 varies depending on the use ofthe product. In the case of certain foam adhesive products, preferablythe thickness of adhesive layer 12 is greater than 250 microns. Morepreferably, the thickness is greater than 500 microns. In the case of asingle layer of non-foamed transfer adhesive, the adhesive layerpreferably has a thickness of 2 to 5 mils (51 to 127 microns), althoughother thicknesses may also be used.

The adhesive layer 12 utilized in the invention is at least partiallycrosslinked by electron beam (“E-beam”) radiation, although additionalcrosslinking means (e.g., chemical, heat, gamma radiation, and/orultraviolet and/or visible radiation) may also be used. The adhesivelayer 12 is crosslinked to impart more desirable characteristics (e.g.,increased strength) to the double-sided adhesive tape 10. One method ofcrosslinking is using electron-beam radiation. E-Beam radiation isadvantageous because it can crosslink polymers that other methodscannot, such as highly pigmented adhesives, adhesives with fillers, andrelatively thick layers of adhesives.

E-Beam radiation causes crosslinking of the adhesive layer by initiatinga free-radical chain reaction. Ionizing particulate radiation from theE-Beam is absorbed directly in the polymer and generates free radicalsthat initiate the crosslinking process. Generally, electron energies ofat least about 100 kiloelectron volts (keV) are necessary to breakchemical bonds and ionize, or excite, components of the polymer system.The scattered electrons that are produced lead to a large population offree radicals dispersed throughout the adhesive. These free radicalsinitiate crosslinking reactions (e.g., free-radical polymerization,radical-radical coupling), which results in a three-dimensionallycrosslinked polymer.

An E-Beam processing unit supplies the radiation for this process.Generally, a processing unit includes a power supply and an E-Beamacceleration tube. The power supply increases and rectifies the current,and the accelerator generates and focuses the E-Beam and controls thescanning. The E-Beam may be produced, for example, by energizing atungsten filament with high voltage. This causes electrons to beproduced at high rates. These electrons are then concentrated to form ahigh energy beam and are accelerated to full velocity inside theelectron gun. Electromagnets on the sides of the accelerator tube allowdeflection, or scanning, of the beam.

Scanning widths and depths typically vary from about 61-183 centimeters(cm) to about 10-15 cm, respectively. The scanner opening is coveredwith a thin metal foil, usually titanium, which allows passage ofelectrons, but maintains a high vacuum in the processing chamber.Characteristic power, current, and dose rates of accelerators are about200-500 keV, about 25-200 milliamps (mA), and about 1-10 megarads(Mrads), respectively. To minimize peroxide formation, the processchamber should be kept at as low an oxygen content as is practical, forexample, by nitrogen purging, although this is not a requirement.

After e-beam treatment the resultant double-sided adhesive tape can bewound into a roll, e.g., as shown in FIG. 3. Further converting stepssuch as, for example, slitting and/or packaging may also be carried outat this point.

SELECT EMBODIMENTS OF THE PRESENT DISCLOSURE

In one aspect, the present disclosure provides a method of making anadhesive article, the method comprising:

providing a backing having first and second opposed major surfaces,wherein a first silicone release layer is disposed on the first majorsurface, wherein a second silicone release layer is disposed on thesecond major surface, and wherein the second silicone release layerfurther comprises a compound represented by the formula:

-   -   wherein        -   R¹ represents a divalent hydrocarbon radical having from 2            to 40 carbon atoms or covalent bond;        -   R² represents a monovalent or divalent            poly(dimethylsiloxane) moiety;        -   X represents —NH— or a covalent bond;        -   R_(f) represents a perfluorinated group having from 3 to 5            carbon atoms; and        -   y is 1 or 2;

disposing an adhesive layer onto the first silicone release layer; and

exposing at least the adhesive layer to electron beam radiation within aprocess chamber thereby providing a crosslinked adhesive layer, whereinthe process chamber contains oxygen, wherein the second silicone releaselayer is exposed to the oxygen during crosslinking of the adhesivelayer.

In a second embodiment, the present disclosure provides a methodaccording to the first embodiment, wherein the electron beam radiationis directed from opposing directions at both the adhesive layer and thesecond silicone release layer, respectively.

In a third embodiment, the present disclosure provides a methodaccording to the first or second embodiment, further comprising windingthe crosslinked adhesive layer onto the second silicone release layer.

In a fourth embodiment, the present disclosure provides an adhesivearticle according to any one of the first to third embodiments, whereinthe crosslinked adhesive layer is a pressure-sensitive adhesive layer.

In a fifth embodiment, the present disclosure provides an adhesivearticle made according to any one of the first to fourth embodiments.

In a sixth embodiment, the present disclosure provides an adhesivearticle comprising: a backing having first and second opposed majorsurfaces, wherein a first silicone release layer is disposed on thefirst major surface, wherein a second silicone release layer is disposedon the second major surface, and wherein the second silicone releaselayer further comprises a compound represented by the formula:

-   -   wherein        -   R¹ represents a divalent hydrocarbon radical having from 2            to 40 carbon atoms or covalent bond;        -   R² represents a monovalent or divalent            poly(dimethylsiloxane) moiety;        -   X represents —NH— or a covalent bond;        -   R_(f) represents a perfluorinated group having from 3 to 5            carbon atoms; and        -   y is 1 or 2; and

an adhesive layer sandwiched between the first and second releaselayers.

In a seventh embodiment, the present disclosure provides an adhesivearticle according to the sixth embodiment, wherein R_(f) isperfluorobutyl.

In an eighth embodiment, the present disclosure provides an adhesivearticle according to according to the sixth or seventh embodiment,wherein R¹ has 6 carbon atoms and is aromatic.

In a ninth embodiment, the present disclosure provides an adhesivearticle according to according to the sixth or seventh embodiment,wherein R¹ has from 2 to 12 carbon atoms.

In a tenth embodiment, the present disclosure provides an adhesivearticle according to any one of the sixth to ninth embodiments, whereinR² is a monovalent or divalent poly(dimethylsiloxane) moiety.

In an eleventh embodiment, the present disclosure provides an adhesivearticle according to any one of the sixth to tenth embodiments, whereinthe adhesive layer is a pressure-sensitive adhesive layer.

In a twelfth embodiment, the present disclosure provides a compoundrepresented by the formula:

-   -   wherein        -   R¹ represents a divalent hydrocarbon radical having from 2            to 40 carbon atoms or covalent bond;        -   R² represents a monovalent or divalent            poly(dimethylsiloxane) moiety;        -   X represents —NH— or a covalent bond;        -   R_(f) represents a perfluorinated group having from 3 to 5            carbon atoms; and        -   y is 1 or 2.

In a thirteenth embodiment, the present disclosure provides a compoundaccording to the twelfth or thirteenth embodiment, wherein R_(f) isperfluorobutyl.

In a fourteenth embodiment, the present disclosure provides a compoundaccording to any one of the twelfth or thirteenth embodiment, wherein R¹has 6 carbon atoms and is aromatic.

In a fifteenth embodiment, the present disclosure provides a compoundaccording to any one of the twelfth to fourteenth embodiments, whereinR¹ has from 2 to 12 carbon atoms.

In a sixteenth embodiment, the present disclosure provides a compoundaccording to any one of the twelfth to fifteenth embodiments, wherein R²is a monovalent or divalent poly(dimethylsiloxane) moiety.

Objects and advantages of this disclosure are further illustrated by thefollowing non-limiting examples, but the particular materials andamounts thereof recited in these examples, as well as other conditionsand details, should not be construed to unduly limit this disclosure.

EXAMPLES

Unless otherwise noted, all parts, percentages, ratios, etc. in theExamples and the rest of the specification are by weight. Unlessotherwise indicated, materials used in the examples available fromcommercial suppliers (e.g., Aldrich Chemical Co., Milwaukee, Wis.)and/or can be made by known methods. Materials prepared in the exampleswere analyzed by NMR spectroscopy and were consistent with the givenstructures.

TABLE OF MATERIALS USED IN THE EXAMPLES DESIGNATION DESCRIPTIONKarstedt's Catalyst Platinum-divinyltetramethyldisiloxane complex inxylene, containing between 2.1 and 2.4 weight percent platinumconcentration, available as product code SIP6831.2 from Gelest,Morrisville, Pennsylvania HPMTS 1,1,1,3,3,5,5-heptamethyltrisiloxane,having a boiling point of 134° C. and a purity of 90%, available fromGelest 4-Pentenoic An olefin terminated, liquid, aliphatic acidcarboxylic acid having a molecular weight of 100.1 g/mol and containing0.01-0.2 weight percent alpha-tocopherol as stabilizer, available asproduct code W284300 from Sigma- Aldrich, St. Louis, Missouri10-Undecenoic An olefin terminated aliphatic carboxylic acid acid with amolecular weight of 184.28 g/mol, a melting point of 23-25° C.,available under the product code W324720 from Sigma-Aldrich PTDMSPentamethyldisiloxane, having a boiling point of 86° C., available fromGelest HTPDS400 A hydride-terminated poly(dimethylsiloxane) having amolecular weight of between 400 and 500 g/mol, a viscosity of 2 to 3centiStokes, and 0.5 weight percent H, available as product code DMS-H03from Gelest HTPDS1000 A hydride-terminated poly(dimethylsiloxane) havinga molecular weight of between 1000 and 1100 g/mol, a viscosity of 7 to10 centiStokes, and 0.2 weight percent H, available as product codeDMS-H11 from Gelest HTPDS4000 A hydride-terminatedpoly(dimethylsiloxane) having a molecular weight of between 4000 and5000 grams/mole, a viscosity of 100 centiStokes, and 0.04 weight percentH, available as product code DMS-H11 from Gelest VTSP A divinylterminated silicone polymer with viscosity of 250 to 400 centiStokes, avinyl content of 0.53 to 0.66 weight percent, and containing 150 ppmplatinum, and 0.7 weight percent inhibitor, obtained from Dow CorningCorporation, Midland, Michigan HFSX A liquid, hydride functionalpolysiloxane crosslinker component, 100% solids and having a viscosityat 25° C. of 30 centiStokes, available under the trade designationSYL-OFF 7678 CROSSLINKER from Dow Corning Corporation, Midland, MichiganIOA Isooctyl acrylate AA Acrylic acid FORAL 85 A tackifier resin, theglycerol ester of highly hydrogenated refined wood rosin having asoftening point of 80 to 86° C. and an acid number of between 3 and 10milligrams KOH/gram resin, available under the trade designation FORAL85 from Pinova Incorporated, Brunswick, Georgia Primed A polyester filmhaving a thickness of 51 Polyester micrometers (0.002 inches) and beingprimed Film on one side, available under the trade designation HOSTAPHAN3SAB from Mitsubishi Polyester Film Incorporated, Greer, South Carolina

Test Methods Coating Weight Determination

The coating weight of silicone release coatings was determined using aLab X 3000 XRF Spectrometer (Oxford Instruments, Elk Grove Village,Ill.) to measure the silicone coat weight compared topolydimethylsiloxane (PDMS) coated polyester film standards of knowncoat weights. Results are reported in grams per square meter (gsm).

Extent of Cure by Extraction Method

The weight percent (%) extractable silicone in the release coating,which can be taken as an indicator of the extent of cure, was determinedby calculating the % change in the silicone release coating weightbefore and after extraction with methyl isobutyl ketone (MIBK) for fiveminutes. The silicone release coating weights were determined by X-Rayfluorescence spectrometry as described above. The % extractable siliconewas calculated as follows:

[(a−b)/a]*100=% extractables

where a=initial coating before extraction with MIBK; and b=final coatingafter extraction with MIBK.

Adhesive Test Tape Preparation

The following components were mixed together: 95 parts IOA and 5 partsAA. A plastic pouch (ethylene-vinyl acetate copolymer) was filled withthis mixture, sealed shut, and the filled pouch was exposed to a UV-Airradiation using a blacklight to completely polymerize the adhesive.The pouch and contents were then fed into a counter-rotating 34millimeter twin-screw extruder (Leistritz, Somerset, N.J.) at 149° C.(300° F.). About 33 parts of FORAL 85 per hundred parts adhesive pouchwere also added to the extruder. The resulting composition was hot meltcoated onto the silicone treated surface of an olefin liner, exposed toelectron beam (E-beam) irradiation (9 MegaRads dosage at a voltage of210 kiloelectron volts) to crosslink the adhesive, then covered with asecond, treated olefin liner. The glass transition temperature (T_(g))of the resulting adhesive was 19° C. Later, the resulting article wasused to transfer laminate the adhesive layer to Primed Polyester Film onits primed surface to provide a single coated Adhesive Test Tape withoutany protective cover film.

Release Force of Adhesive Test Tape from Release Liner

The release force between the release liner and the Adhesive Test Tapeof a laminate construction was measured using a 180-degree peel geometryaccording to the manufacturer's instructions as follows. An IMASS SP2100 peel force tester (IMASS, Incorporated, Accord, Mass.) equippedwith a 5.0-pound (2.27-kg) load cell was employed using the followingparameters: a 1 inch (2.54 centimeters) wide test specimen, a peel rateof 90 inches/minute (229 cm/min), a two second delay before dataacquisition, and a five second averaging time. The average of two testspecimens was reported in grams/inches. Testing was done according tothe following conditions.

-   -   A) Seven days at 22° C. (72° F.) and 50% Relative Humidity    -   B) Seven days at 50° C., followed by an equilibration at 22° C.        (72° F.) and 50% Relative Humidity for a minimum of 24 hours        before testing.

Peel Adhesion Strength of Adhesive Test Tape

The peel adhesion strengths of the Adhesive Test Tape from a glass panelwas measured at 72° F. (22° C.) and 50% Relative Humidity, and weredesignated as Peel Adhesion Strength 1 and 3. In addition, a secondsample of the Adhesive Test Tape was first laminated to the releaseliner such that it contacted the release coating layer and exposed tovarious conditions as noted in the Release Force of Adhesive Test Tapefrom Release Liner test method, then evaluated for release force. Uponremoval of the Adhesive Test Tape from the release liner the Tape wasevaluated for its Peel Adhesion Strength as before, with this resultbeing designated as Peel Adhesion Strength 2 and 4.

Testing was done immediately after removal of the Adhesive Test Tapefrom the release liner (within one minute) and applying the test tape toa clean glass plate using a 5 lb (2.3 kg) roller. An IMASS SP 2100Slip/Peel Tester (IMASS, Incorporated, Accord, Mass.) equipped with a 10pound (4.54 kg) load cell was employed using the following parameters:one inch (2.54 cm) wide test specimen, peel rate of 90 inches/minute(229 cm/min), two second delay before data acquisition, 180 peelgeometry, and a ten second averaging time. The average of two testspecimens was reported in grams/inches (g/cm).

Preparation of 1-(1,1,2,2,3,3,4,4,4-Nonafluorobutylsulfonyl)Piperazine

To a 3-neck 3 L round bottom equipped with a mechanical stirrer,addition funnel and a Claisen adaptor with thermocouple and refluxcondenser was added piperazine (486 g, 5642 mmol) and triethylamine (400mL, 2870 mmol). The reaction mixture was heated to 65° C. withcontinuous stirring. Once the reaction mixture reached 50° C.,1,1,2,2,3,3,4,4,4-nonafluorobutane-1-sulfonyl fluoride (500 mL, 2780mmol) was added via addition funnel at such a rate so as to maintain atemperature below 90° C. Upon completion of addition, the temperaturewas raised to 95° C. and the reaction mixture was allowed to stir for 16hr. The vessel was cooled to 50° C. and water (300 mL) was addedfollowed by dichloromethane (500 mL). The resulting biphasic mixture wasallow to stir for 5 min and then allowed to phase separate. The lowerphase was removed, washed 3× with water (300 mL), brine (500 mL), anddried over sodium sulfate (250 g). The resulting yellow solution wasfiltered, solvent was removed via rotary evaporator and distilled at 250mTorr and 80° C. to afford 713 g of1-(1,1,2,2,3,3,4,4,4-nonafluorobutylsulfonyl)piperazine as a whitesolid.

Preparation of Fluoro Additive 1 Precursor (FA1P)

1-(1,1,2,2,3,3,4,4,4-nonafluorobutylsulfonyl)piperazine (185.7 g, 504mmol, 1.01 equivalents), pent-4-enoic acid (50 g, 499 mmol, 1equivalent), and mesitylene (125 mL) were added to a 1 L round bottomflask equipped with a magnetic stir bar, Dean-Stark trap, and refluxcondenser. The reaction mixture was slowly heated to 140° C. and heldfor 30 minutes, then to 200° C. in 10° C. intervals over a period of 3hours with slow evolution of water. The temperature was maintained at200° C. for 12 hours. The mixture was then cooled to afford, withoutfurther purification,1-(4-((perfluorobutyl)sulfonyl)piperazin-1-yl)pent-4-en-1-one (225 g,FA1P) as a white solid.

Preparation of Fluoro Additive 6 Precursor (FA6P)

1-(1,1,2,2,3,3,4,4,4-nonafluorobutylsulfonyl)piperazine (84.22 g, 228.7mmol, 1.01 equivalents), undecen-10-enoic acid (41.7 g, 226.4 mmol, 1equivalent), and mesitylene (10 mL) were added to a 250 mL round bottomflask equipped with a magnetic stir bar, dean-stark trap and refluxcondenser. The reaction mixture was slowly heated to 140° C., thetemperature was held for 30 minutes and then raised to 200° C. in 10° C.intervals over a period of 3 hours with slow evolution of water. Thetemperature was maintained at 200° C. for 12 hours. The mixture wascooled to afford, without further purification,1-(4-((perfluorobutyl)sulfonyl)piperazin-1-yl)undec-10-en-1-one (120 g,FAP6) as a dark brown solid.

Example 1 Preparation of Fluoro Additive 1 (FA1)5-(1,1,3,3,5,5,5-heptamethyltrisiloxanyl)-1-(4-((perfluorobutyl)sulfonyl)piperazin-1-yl)pentan-1-one

The following were added to a 5 L, 3-neck round bottom flask equippedwith a magnetic stir bar, thermocouple, reflux condenser, and anaddition funnel: 900 g (2 mol, 1 equivalent) of FA1P, 100 g (10 mmol ofPt) of Karstedt's Catalyst solution, and 1 L of toluene. Next, 550 g(2.47 mol, 1.24 equivalents) of HPMTS was added with vigorous stirringvia the addition funnel at a rate such that the temperature did notexceed 45° C. The resulting dark colored solution was allowed to stir at23° C. for 18 hours after which solvent and excess reagent were removedunder vacuum with the aid of a rotary evaporator to afford, withoutfurther purification, 1.34 kg of5-(1,1,3,3,5,5,5-heptamethyltrisiloxanyl)-1-(4-((perfluorobutyl)sulfonyl)piperazin-1-yl)pentan-1-one(FA1) as a dark oil.

Example 2 Preparation of Fluoro Additive 2 (FA2)

FA2 was prepared in the same manner as FA1, with the followingmodifications: a 500 mL round bottom flask was used, 20 g (44.4 mmol, 1equivalent) of FA1P, 0.0855 g (8.8 micromoles of Pt) of Karstedt'scatalyst solution, 22 mL of toluene, and 7.9 g (53.3 mmol, 1.2equivalents) of PTDMS were combined to afford, without furtherpurification, 26.6 g of5-(1,1,3,3,3-pentamethyldisiloxanyl)-1-(4-((perfluorobutyl)sulfonyl)piperazin-1-yl)pentan-1-one(FA2) as a dark oil.

Example 3 Preparation of Fluoro Additive 3 (FA3)

FA3 was prepared in the same manner as FA2, with the followingmodification. 9.6 g (22.2 mmol, 0.5 equivalent) of HTPDS400 was used inplace of PTDMS to afford, without further purification, 29.6 g of5,5′-(HTPDS400)bis(1-(4-((perfluorobutyl)sulfonyl)piperazin-1-yl)pentan-1-one)(FA3) as a dark solid.

Example 4 Preparation of Fluoro Additive 4 (FA4)

FA4 was prepared in the same manner as FA2, with the followingmodification. 22.7 g (22.2 mmol, 0.5 equivalent) of HTPDS1000 was usedin place of PTDMS to afford, without further purification, 42.7 g of5,5′-(HTPDS1000)bis(1-(4-((perfluorobutyl)sulfonyl)piperazin-1-yl)pentan-1-one)(FA4) as a dark solid.

Example 5 Preparation of Fluoro Additive 5 (FA5)

FA5 was prepared in the same manner as FA2, with the followingmodifications. 2.0 g (4.44 mmol, 1 equivalent) of FA1P, 0.00855 g (0.88micromoles of Pt) of Karstedt's catalyst solution, 22.2 mL of toluene,and 10.1 g (2.22 mmol, 0.5 equivalent) of HTPDS4000 were used to afford,without further purification, 12.1 g of5,5′-(HTPDS4000)bis(1-(4-((perfluorobutyl)sulfonyl)piperazin-1-yl)pentan-1-one)(FA5) as a dark oil.

Example 6 Preparation of Fluoro Additive 6 (FA6)

FA6 was prepared in the same manner as FA2, with the followingmodifications. 11.8 g (22.2 mmol, 1 equivalent) of FA6P, 0.043 grams(4.4 micromoles of Pt) of Karstedt's catalyst solution, 11 mL oftoluene, and 6.13 g (26.6 mL, 1.24 equivalents) of HPMTS were employedto afford, without further purification, 17.9 g of11-(1,1,3,3,5,5,5-heptamethyltrisiloxanyl)-1-(4-((perfluorobutyl)sulfonyl)piperazin-1-yl)undecan-1-one(FA6) as a dark solid.

Example 7 Preparation of Fluoro Additive 7 (FA7)

FA7 was prepared in the same manner as FA6, with the followingmodification. 4.16 g (26.6 mmol, 1.24 equivalents) of PTDMS was used inplace of HPMTS to afford, without further purification, 15.7 g of11-(1,1,3,3,3-pentamethyldisiloxanyl)-1-(4-((perfluorobutyl)sulfonyl)piperazin-1-yl)undecan-1-one(FA7) as a dark solid.

Example 8 Preparation of Fluoro Additive 8 (FA8)

FA8 was prepared in the same manner as FA6, with the followingmodification. 5.05 g (1.11 mmol, 0.5 equivalent) of HTPDS4000 was usedin place of HPMTS to afford, without further purification, 16.9 g of11,11′-(HTPDS4000)-1-(4-((perfluorobutyl)sulfonyl)piperazin-1-yl)undecan-1-one(FA8) as a dark oil.

Example 9 Preparation of Fluoro Additive 9 (FA9)

FA9 was prepared in the same manner as FA6, with the followingmodification. 4.8 g (11.1 mmol, 0.5 equivalent) of HTPDS400 was used inplace of HPMTS to afford, without further purification, 16.6 g of11,11′-(HTPDS400)-1-(4-((perfluorobutyl)sulfonyl)piperazin-1-yl)undecan-1-one(FA9) as a dark solid.

Example 10 Preparation of Fluoro Additive 10 (FA10)

FA10 was prepared in the same manner as FA6, with the followingmodification. 11.36 g (11.1 mmol, 0.5 equivalent) of HTPDS1000 was usedin place of HPMTS to afford, without further purification, 23 g of11,11′-(HTPDS1000)-1-(4-((perfluorobutyl)sulfonyl)piperazin-1-yl)undecan-1-one(FA10) as a dark solid.

Examples 11 and 12

The following were combined in ajar and mixed to give a homogeneoussolution: 100 grams of VTSP, 2.54 grams HFSX at a hydride:vinyl ratio of1.2:1, and either 2.1 grams (2 weight percent) or 4.28 grams (4 weightpercent) of FA1. This solution was coated at 100 weight percent solidsonto the primed side of Primed Polyester Film using a five roll coatingstation. The silicone coating was then cured in an oven at 127° C. (260°F.) for 12 seconds. Coating weights of approximately 2.0 grams/squaremeter were obtained with less than 5 weight percent extractables. Thecoated, cured release liners thus obtained were stored for one week at22° C. (72° F.) and 50% relative humidity) before exposure to electronbeam (e-beam) irradiation.

Next, the coated, cured release liner was exposed to e-beam radiation onthe side having the release coating composition which contained FA1. AnELECTROCURTAIN CB-300 E-beam unit (Energy Sciences Incorporated,Wilmington, Mass.) was employed, the accelerating voltage was 210kiloelectron volts, and a dose of 9 megaRads was provided. The oxygenconcentration in the nitrogen-inerted E-beam chamber was maintainedbetween 8-15 ppm oxygen as measured by an Alpha Omega Series 3000 TraceOxygen Analyzer (Alpha Omega Instruments Corporation, Lincoln, R.I.).The E-beam treated release liner was then immediately (within 30seconds) laminated to the Adhesive Test Tape by hand using a rubberroller to ensure intimate contact. In this way, the adhesive of theAdhesive Test Tape was in direct contact with the cured, E-beam treatedrelease coating of the release liner. The resulting laminateconstruction was then evaluated for release force, as well as the peeladhesion strength of the Adhesive Test Tape both before lamination, andafter lamination to the release liner followed by exposure to variousconditions, as described in the test methods above.

Comparative Example A

Example 11 was repeated with the following modification. FA1 was notused.

Examples 11 and 12, and Comparative Example A were tested according tothe RELEASE FORCE OF ADHESIVE TEST TAPE FROM RELEASE LINER and PEELADHESION STRENGTH OF ADHESIVE TEST TAPE procedures. Results are reportedin Table 1, below. Peel Adhesion Strength 1 of the test tape from glasswas 3024 grams/inch (1191 g/cm).

TABLE 1 RELEASE FORCE, PEEL ADHESION STRENGTH 2, grams/inch (g/cm)grams/inch (g/cm) EXAMPLE DESCRIPTION Condition A Condition B ConditionA Condition B Comparative 0% FA1 902 (355) 1069 (421) 2779 (1094) 3010(1185) Example A 11 2% FA1 108 (42.5) 246 (96.9) 3170 (1248) 3316 (1306)12 4% FA1 111 (43.7) 188 (74.0) 3179 (1252) 3232 (1347)

Examples 13-24

The following were combined in ajar and mixed to give a homogeneoussolution: 9.72 grams of VTSP, 0.278 grams HFSX at a hydride:vinyl ratioof 1.35:1, 28.36 grams of heptane, 7.09 grams of methyl ethyl ketone andeither 0.044 grams (2 weight percent) or 0.088 grams (4 weight percent)of FA1, FA2, FA4, FA6, FA7 or FA10. The solutions were coated at 22weight percent solids onto the primed side of Primed Polyester Filmusing a #8 Meyer Rod (0.72 mil (18 microns) nominal wet film thickness).The silicone coating was then cured in an oven at 120° C. for 2 minutes.Coating weights of approximately 2.0 grams/square meter were obtainedwith less than 5 weight percent extractables. The coated, cured releaseliners thus obtained were stored for one week at 22° C. (72° F.) and 50%relative humidity) before exposure to electron beam (E-beam)irradiation.

Next, the coated, cured release liner was exposed to e-beam radiation onthe side having the release coating composition which contained FA1,FA2, FA4, FA6, FA7 or FA10. An ELECTROCURTAIN CB-300 E-beam unit (EnergySciences Incorporated, Wilmington, Mass.) was employed, the acceleratingvoltage was 210 kiloelectron volts, and a dose of 9 megaRads wasprovided. The oxygen concentration in the nitrogen-inerted E-beamchamber was maintained between 8-15 ppm oxygen as measured by an AlphaOmega Series 3000 Trace Oxygen Analyzer (Alpha Omega InstrumentsCorporation, Lincoln, R.I.). The E-beam treated release liner was thenimmediately (within 30 seconds) laminated to the Adhesive Test Tape byhand using a rubber roller to ensure intimate contact. In this way, theadhesive of the Adhesive Test Tape was in direct contact with the cured,E-beam treated release coating of the release liner. The resultinglaminate construction was then evaluated for release force, as well asthe peel adhesion strength of the Adhesive Test Tape both beforelamination, and after lamination to the release liner followed byexposure to various conditions, as described in the test methods above.

Comparative Example B

Example 13 was repeated with the following modification. FA1 was notused.

Examples 13-24, and Comparative Example B were tested according to theRELEASE FORCE OF ADHESIVE TEST TAPE FROM RELEASE LINER and PEEL ADHESIONSTRENGTH OF ADHESIVE TEST TAPE procedures. Results are reported in Table2, below, wherein Peel Adhesion Strength 3 of the test tape from glasswas 3515.3 grams/inch (1384 g/cm).

TABLE 2 RELEASE FORCE, PEEL ADHESION STRENGTH 4, grams/inch (g/cm)grams/inch (g/cm) EXAMPLE DESCRIPTION Condition A Condition B ConditionA Condition B Comparative 0% FA1 662 (261) 412 (162) 3185 (1254) 3165(1246) Example B 13 2% FA1 59 (23) 58 (23) 3437 (1353) 3626 (1428) 14 4%FA1 38 (15) 48 (19) 3447 (1357) 3615 (1423) 15 2% FA2 81 (32) 70 (27)3449 (1358) 3486 (1372) 16 4% FA2 48 (19) 52 (20) 3381 (1331) 3246(1278) 17 2% FA4 57 (22) 67 (26) 3235 (1273) 3589 (1413) 18 4% FA4 43(17) 52 (20) 3263 (1285) 3525 (1388) 19 2% FA6 51 (20) 58 (23) 3393(1336) 3627 (1428) 20 4% FA6 21 (8) 34 (13) 3293 (1296) 3589 (1413) 212% FA7 73 (29) 63 (25) 3515 (1384) 3644 (1435) 22 4% FA7 23 (9) 22 (9)3345 (1317) 3427 (1349) 23 2% FA10 79 (31) 83 (32) 3206 (1262) 3595(1415) 24 4% FA10 78 (31) 77 (30) 3324 (1309) 3340 (1315)

All cited references, patents, and patent applications in the aboveapplication for letters patent are herein incorporated by reference intheir entirety in a consistent manner. In the event of inconsistenciesor contradictions between portions of the incorporated references andthis application, the information in the preceding description shallcontrol. The preceding description, given in order to enable one ofordinary skill in the art to practice the claimed disclosure, is not tobe construed as limiting the scope of the disclosure, which is definedby the claims and all equivalents thereto.

What is claimed is:
 1. A method of making an adhesive article, themethod comprising: providing a backing having first and second opposedmajor surfaces, wherein a first silicone release layer is disposed onthe first major surface, wherein a second silicone release layer isdisposed on the second major surface, and wherein the second siliconerelease layer further comprises a compound represented by the formula:

wherein R¹ represents a divalent hydrocarbon radical having from 2 to 40carbon atoms or covalent bond; R² represents a monovalent or divalentpoly(dimethylsiloxane) moiety; X represents —NH— or a covalent bond;R_(f) represents a perfluorinated group having from 3 to 5 carbon atoms;and y is 1 or 2; disposing an adhesive layer onto the first siliconerelease layer; and exposing at least the adhesive layer to electron beamradiation within a process chamber thereby providing a crosslinkedadhesive layer, wherein the process chamber contains oxygen, wherein thesecond silicone release layer is exposed to the oxygen duringcrosslinking of the adhesive layer.
 2. The method of claim 1, whereinthe electron beam radiation is directed from opposing directions at boththe adhesive layer and the second silicone release layer, respectively.3. The method of claim 1, further comprising winding the crosslinkedadhesive layer onto the second silicone release layer.
 4. The method ofclaim 1, wherein the crosslinked adhesive layer is a pressure-sensitiveadhesive layer.
 5. An adhesive article made according to the method ofclaim
 3. 6. An adhesive article comprising: a backing having first andsecond opposed major surfaces, wherein a first silicone release layer isdisposed on the first major surface, wherein a second silicone releaselayer is disposed on the second major surface, and wherein the secondsilicone release layer further comprises a compound represented by theformula:

wherein R¹ represents a divalent hydrocarbon radical having from 2 to 40carbon atoms or covalent bond; R² represents a monovalent or divalentpoly(dimethylsiloxane) moiety; X represents —NH— or a covalent bond;R_(f) represents a perfluorinated group having from 3 to 5 carbon atoms;and y is 1 or 2; and an adhesive layer sandwiched between the first andsecond release layers.
 7. The adhesive article of claim 6, wherein R_(f)is perfluorobutyl.
 8. The adhesive article of claim 6, wherein R¹ has 6carbon atoms and is aromatic.
 9. The adhesive article of claim 6,wherein R¹ has from 2 to 12 carbon atoms.
 10. The adhesive article ofclaim 6, wherein R² is a monovalent or divalent poly(dimethylsiloxane)moiety.
 11. The adhesive article of claim 6, wherein the adhesive layeris a pressure-sensitive adhesive layer.
 12. A compound represented bythe formula:

wherein R¹ represents a divalent hydrocarbon radical having from 2 to 40carbon atoms or covalent bond; R² represents a monovalent or divalentpoly(dimethylsiloxane) moiety; X represents —NH— or a covalent bond;R_(f) represents a perfluorinated group having from 3 to 5 carbon atoms;and y is 1 or
 2. 13. The compound of claim 12, wherein R_(f) isperfluorobutyl.
 14. The compound of claim 12, wherein R¹ has 6 carbonatoms and is aromatic.
 15. The compound of claim 12, wherein R¹ has from2 to 12 carbon atoms.
 16. The compound of claim 12, wherein R² is amonovalent or divalent poly(dimethylsiloxane) moiety.